Our next question is: My 2-year-old Chihuahua loves his bully stick in the 6" size. I'm wondering since he goes through them so quickly if he's hurting his teeth, I've noticed that his teeth are actually getting smaller. It concerns me that you mentioned his teeth are getting smaller; it's not normal for an adult tooth to actually regress in size. My concern is that possibly what's happening due to excessive wear and tear at the teeth, they may actually be fracturing due to chewing on this hard surface.